Pumpjack systems are well-known in the oil and gas industry. These systems are designed to pump fluid out of a well and typically have separate assemblies and controllers to measure and control characteristics of pumpjack equipment including: measuring the speed at which the system is pumping, turning the pump on or off based on the weight of the fluid in the production tubing, measuring strain on the rod itself, or a combination of characteristics, such as measuring the strain and location of the polished rod relative to ground level. Measuring and controlling these characteristics is important for efficiency, health monitoring, and safety of the pumpjack. If the characteristics are not monitored properly, damage can be caused to parts of the pumpjack.
In measuring these characteristics, it is sometimes desirable to obtain high frequency data for improved diagnostics, in the event an anomaly occurs. For example, if there is a sudden spike in the strain on the polished rod, it can be helpful to record high-speed data surrounding the anomaly to aid in pinpointing the cause of the spike, and to determine whether or not it is a potential issue. Furthermore, it is desirable to monitor multiple characteristics of a pumpjack system and to store this data, so as to develop a predictive maintenance procedure for the system.
Wired systems have been used for this application, but due to the nature of the relative motion between parts in a pumpjack system, wires frequently break and need to be repaired. To address this issue, wireless systems were developed to collect the pumpjack operating characteristics.
One example of a current system includes U.S. Pat. No. 7,032,659 B2, which discloses a wireless system for pump control. The disclosed systems measures strain and position of a pumpjack structure and transmits control signals to a motor control panel. The system is mounted to the walking beam of a pumpjack structure. The system uses a transmitter in a control unit and a receiver in a motor control panel, and is therefore limited to mono-directional communications. In addition, the system only accounts for the measurements of strain and position, and does not measure other operational characteristics of the pumpjack system. Furthermore, the system is large, requiring that it be mounted to the top of the walking beam of the pumpjack system. The disclosure does not address transmission power, data rate or power consumption. The power consumption of a high-power transmission system required for the wide-open regions and indirect line of sight installations typical of this application, combined with the power consumption of a high-frequency wireless system, have precluded existing wireless systems from successful implementation in the field. In addition, because pumpjacks are often located in remote areas, changing batteries may be costly.
Thus, there is a need for a wireless data system that can directly measure operating characteristics of the pumpjack, process a pump control signal from that data, and send the raw data and/or the processed signal for pump control. There is also a need to collect data at sufficiently high data rates to capture rod resonance frequencies and down-hole impact signatures. Further, there is a need for a transceiver-based system that uses bi-directional communications to enable altering data collection parameters such as data rate, data quality, transmission energy, etc. for purposes of improving diagnostics when needed while managing consumed energy when not. There is also a need to wirelessly transmit this data to a central station for long-term data storage to enable implementation of predictive maintenance techniques for the pump system. Furthermore, to ensure successful implementation in the field, there is a need for a system that minimizes consumed energy to ensure long battery life, while meeting the power transmission and data rate requirements of this application.